What I understand is that the templates for virtual machines are no longer listed in the vCenter Server inventory.But as you are having the templates in datastore,try this
->double-click the datastore that the template is stored.
->Navigate the datastore to the folder containing the template.
->Select the template configuration file, which has a .vmtx extension. Right-click it and select Add to Inventory.
Template will now appear in inventory listing.Hope this helps!!
Regards,
SatyS
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